British health authorities on Sunday urged people to wash their clothing and possessions as a precaution if they visited a restaurant and pub in the English city of Salisbury, where a Russian ex-spy and his daughter were poisoned with a nerve agent.

Public Health England issued advice for anyone who went to either the Zizzi restaurant or The Mill pub at certain hours of March 4 and 5. Ex-spy Sergei Skripal and his 33-year-old daughter, Yulia, reportedly ate at Zizzi before falling critically ill on March 4.

Advertisement

"While there is no immediate health risk to anyone who may have been in either of these locations, it is possible, but unlikely, that any of the substance which has come into contact with clothing or belongings could still be present in minute amounts and therefore contaminate your skin," the statement said.

The health agency added that any clothing should be washed in "an ordinary washing machine using your regular detergent."

It also said to "wipe personal items such as phones, handbags and other electronic items with cleansing or baby wipes and dispose of the wipes in the bin."

BBC reported that up to 500 people may have to take these precautions. Officials haven't said what type of nerve agent was used.

Home Secretary Amber Rudd said Saturday evening it is still "too early" to determine who is to blame for the attack. Senior government officials have vowed to respond robustly if the Russian government is found to be responsible.

Rudd said more than 250 counterterrorism officers are on the scene evaluating more than 240 pieces of evidence and interviewing about 200 witnesses.

The officers are backed by roughly 180 military personnel providing logistical support, including the removal of ambulances feared to possibly be contaminated by the nerve agent.

Police are looking for clues to what sickened Skripal, 66, a Russian ex-military intelligence specialist who in 2006 was convicted in Russia of spying for Britain, and his daughter.

Skripal was imprisoned inside Russia until he was freed in a 2010 spy swap and settled in England. He had stayed out of the public eye since then.

The father and daughter were found unconscious March 4 on a bench in Salisbury. Skripal lived in the town, located 90 miles southwest of London.